dynamic performance with reference to indicated
horse-power, and of her dynamic duty with re-
ference to her consumption of fuel.

I am, Gentlemen, yours very obediently,
CHARLES ATHERTON.

Proceedings of Societies.

MANCHESTER LITERARY AND PHILOSOPHICAL

SOCIETY.

municated by me.to the Institution of Civil Englass jar-the second of the kind which I had gineers, and published in April, 1854, present tried, and which would not hold its charge for results conclusively demonstrative of the SUPERIOR half a day). I found from 13 to 14° of torsion CAPABILITIES of large ships in the commercial required to bring the index to zero when urged point of view to which Mr. Cheverton now revives aside by the electromotive force of ten zinc-copper attention; in fact, these papers were written by water-cells. The Leyden phial held so well, that me when the keel of the Great Eastern was being the sensibility of the electrometer measured in laid, and when scientific and speculative enthusiasm that way did not fall more than from 13° tol›, were at their height, not merely to confirm the in three days. The atmospheric effect ranl use of, but to caution the public as to the misuse from 30° to above 420° during the four d which then appeared to me to threaten the introwhich I had to test it-that is to say, the electroduction of leviathan ships. If Mr. Cheverton will QUARTERLY MEETING, Oct. 18th, 1859.-William motive force per foot of air measured horizontally now prosecute these investigations, taking, as he Fairbairn, Esq., F.R.S., &c., President, in the from the side of the house was from nine to one suggests, "the simple displacement as the factor chair. The President announced the formation hundred and twenty-six zinc copper water cells. and not the power thereof," the result will, I of a Mathematical and Physical Section in conThe weather was almost perfectly settled, either venture to say, be the reverse of what he antici-nexion with the Society. Dr. F. Crace Calvert calm, or with slight east wind, and in general an pates as respects doing justice to the commercial presented, in the name of Mr. Arnaudon (from easterly haze in the air. The electrometer twice capabilities of the Great Eastern. But this Turin), a paper, and samples of green colours within half an hour went above 420°, there being leviathan is now afloat, ready to test the truth or used in painting and printing, and especially at the time a fresh temporary breeze from the fallacy of the theories that have been advanced, referred to two new chrome greens, one of which east. What I had previously observed regarding and although her capabilities for sea service as is a new compound, corresponding to the monohy- the effect of east wind was amply confirmed. respects the mutual relation of displacement, drate of sesquioxyde of chrome Cr3 03 HO. The Invariably the electrometer showed very high power, speed, and coal have not yet been conclu- author commences in his work to point out the positive in fine weather, before and during east wind. sively determined, it appears from the data of her qualities which a good green ought to possess, It generally rose very much, shortly before a slight passage from the Bill of Portland to Tuscar order to be suitable for painting. puff of wind from that quarter, and continued (MECHANICS' MAGAZINE, No. 42, p. 242 and 252) reviews in a few words the different greens which high till the breeze would begin to abate. I that with a displacement of (say) 17,500 tons, the are found at present in the market, together with never once observed the electrometer going up distance, 400 nautical miles, was performed in 32 the nature and properties of the same. Begin unsually high during fair weather without east hours with a consumption of fuel at the rate of ning with the history of the works already pub-wind following immediately. One evening in 250 tons per 24 hours, or 208-3 cwts. per hour, lished on this subject, he next gives the descrip- August I did not perceive the east wind at all, being at the average speed of 124 knots per hour, tion of his process for preparing his monohydrate when warned by the electrometer to expect it; with a consumption of fuel at the rate of 16.66 of sesquioxyde of chrome, and which consists in but I took the precaution of bringing my boat up ewts. per knot. These data give a co-efficient of exposing the bichromate of potash mixed with to a safe part of the beach, and immediately dynamic duty with reference to coal (by the phosphoric acid and any desoxydizing agent (for found by waves coming in that the east wind must example, ammonia) for some time to the action of be blowing a short distance out at sea, although -), equal to 6326. heat. The soluble salts are then removed by it did not get so far as the shore. I made a W washing. slight commencement of the electro-geodesy which I pointed out as desirable at the British Association, and in the course of two days, namely, October 3rd and 4th, got some very decided results.

formula

On this assumption that the steaming speed of 12) knots per hour requires 250 tons of coal per day; will require 281 tons per day;

13

14

15

351
432

it is, however, to be hoped that the construction of the engines and boilers of the Great Eastern is such as admits of the introduction of modern improvements, whereby the consumption of fuel with reference to speed may be greatly reduced.

It may be observed that on the passage to Holyhead, the engines were not continuously worked up to their full power, and, therefore, that the capability of the ship for continuous high speed was not fully developed. This consideration, however, will not materially affect the coefficient of dynamic duty above deduced, for the consumption of fuel per hour when working at fall power would be increased in about the same proportion as the cube of the speed would be increased, and, consequently, the co-efficient of dynamic duty by the above formula remains very nearly constant at whatever speed the ship may be driven, so long as the displacement is not materially altered.

The circumstances of the passage to Holyhead do not appear to have admitted of exact data being obtained as to the rate of consumption of fuel per indicated horse-power per hour by the screw and paddle-wheel engines respectively; but it being understood that the screw engines were worked with steam partially superheated, it is probable that the consumption may not have exceeded 31 lbs. per indicated horse-power per hour, and on this assumption the co-efficient of dynamic performance with reference to displacement and power would be about 200. This is a low co-efficient for a mercantile steam-ship, but it is about as high as I have ever known to be realized by any vessel of which the ratio of mean draught to breadth was so small as in this case of the Great Eastern, namely, only 23 to 84, or 1 to 3.65. It may be expected to improve as the vessel shall be loaded down to a deeper draught. The question involving, as it does, the merits of the type of form of the ship, is of great importance, and it is to be hoped that the Great Eastern will not be allowed to go to her moorings at Southampton without having gone through the usual ordeal of a trial by repeated runs over the measured knot in Stokes' Bay, in addition to her sea-trials for determining the present co-efficients of her

in

Then he

The green so prepared has not only a beautiful shade, but like that of Mr. Guignet (made by decomposing the borate of oxyde of chrome by water) possesses the curious property of remaining green under the influence of artificial light. Dr. Calvert also presented some muslins printed by M. Camille Kachlin, of Mulhouse, with fuchsine, a product obtained from the aniline of coal tar. This colour was very remarkable from the exquisite bloom of the pink shade abtained when fixed with albumen.

The following extract of a letter received from Professor W. Thomson, F.R.S., Honorary Member of the Society, &c., was read by Dr. Joule.

Macfarlane, and one of my former laboratory and Agamemnon assistants, Russel, came down to Arran for the purpose. Mr. Russel and I went up Goatfell on the 3rd inst. with the portable electrometer and made observations, while Mr. Macfarlane remained at Invercloy, constantly observing and recording the indications

distant on the road beside the sea was 97 and 96

of the house electrometer. On the 4th inst. the same process was continued to observe simultaneously at the house and at one or other of several stations on the way up Goatfell. I have "I have a very simple domestic' apparatus by not yet reduced all the observations, but I see which I can observe atmospheric electricity in an enough to leave no doubt whatever but that cloudeasy way. It consists merely of an insulated can less masses of air at no great distance from the of water to set on a table or window-sill inside, earth, certainly not more than a mile or two, and discharge by a small pipe through a fine influence the electrometer largely by electricity nozzle two or three feet from the wall. With which they carry. This I conclude because I find only about ten inches head of water and a disno constancy in the relation between the simulcharge so slow as to give no trouble in replenish-taneous electrometric indications at the different ing the can with water, the atmospheric effect is stations. Between the house and the nearest collected so quickly that any difference of station the relative variation was least. Between potentials between the insulated conductor and the house and a station about half way up Goatthe air at the place where the stream from the fell, at a distance estimated at two miles and a nozzle breaks into drops is done away with in my half in a right line, the number expressing the apparatus at the rate of five per cent. per half ratio varied from about 113 to 360 in the course second, or even faster. Hence a very moderate of about three hours. On two different mornings degree of insulation is sensibly as good as perfect, the ratio of house to a station about sixty yards so far as observing the atmospheric effect is concerned. It is easy, by my plan of drying the at- respectively. On the afternoon of the 4th inst., mosphere round the insulating stems by means of during a fresh temporary breeze of east wind, pumice-stone moistened with sulphuric acid, to blowing up a little spray as far as the road station, insure a degree of insulation in all weathers, by most of which would fall short of the house, the which not more than five per cent. per minute ratio was 108 in favour of the house electrometer will be lost by it from the atmospheric apparatus-both standing at the time very high-the at any time. A little attention to keep the outer part of the conductor clear of spider lines is necessary. The apparatus I employed at Invercloy stood on a table beside a window on the second floor, which was kept open about an inch to let the discharging tube project out without coming in contact with the frame. The nozzle was only about two feet and a half from the wall, and nearly on a level with the window-sill. The divided ring electrometer stood on the table beside it, and acted in a very satisfactory way (as forwarded a telegram to J. R. Stebbing, Esq., to the The Chairman of the Great Eastern Company has I had supplied it with a Leyden phial consisting effect that the great ship sailed from Holyhead on of a common thin white glass shade, which insu- Wednesday at 12 30 for Southampton, where she may lated remarkably well, instead of the German | be expected this evening (Friday).

house about 350°. I have no doubt but that this was owing to the negative electricity carried by the spray from the sea, which would diminish relatively the indications of the road electrometer.""

A paper was read by Mr. Hopkins, entitled "On Irregularities in the Winter Temperature of the British Islands."

DR. SAMUEL NEWINGTON, of Ridgway Ticehurst
Sussex, has just completed a patent for the ap-
paratus for distributing seeds and manure repre-
sented in the annexed engraving. This apparatus
is applicable for distributing guano, lime, and all
kinds of dry pulverized manure, and for dis-
tributing corn, grass, and other like seeds broad-
cast. a is the hopper, to the upper part of which
the shafts bb are attached. The side a' of the
hopper turns at its upper edge on the hinge c, so
that the lowest edge of the side a' can be moved
to or from the lower part of the side a2; to the
lower part of the moveable side a' are bolted
projecting pieces d d. A vibratory motion is com-
municated to the side a' by projecting blades, or
teeth, e, on the axis f. On this axis there are
two ratchet wheels, into which pawls (turning on
pins fixed to the bosses of the wheels i) are
pressed by means of springs, which are also fixed
to the bosses of the wheels, so that the axis f is
only caused to rotate when the machine is drawn
forwards; the rotation of the axis f causes the
projecting blades e upon it to strike in succession AN IMPROVED METHOD OF RETARDING in the table, resulted as follows:-On an incline

seed or manure is placed inside the hopper, and, worked from the foot-plate by the connection
attached to the moveable side a', and holes are D, which being separate from the connection B,
formed through the side a' near its lowest edge, it will be seen that one or both of the retarding
and through the box containing the seed, and as forces may be used at pleasure. The steam from
the machine moves forwards the seed or manure the pipe C passes to cylinder E, actuating the
is shaken out through these holes into funnels piston H and levers K, &c., and break-blocks N,
carried from the fixed ends of the hopper, and is which may be applied to all the wheels if desired,
by them guided into the furrows, or the seed or but by preference they are shown attached to the
manure may fall on the platform 7, and be guided leading and trailing wheels only of passenger
into the furrows by pieces of wood screwed on the engines. On the steam being released, the weight
board at intervals. The holes in the side a' and of piston, rods, and levers will free the break-blocks
in the box are kept clear by means of wires; from the wheels.
these wires are fixed to a bar passing along the
upper part of the hopper, and pass down through
the seed or manure to the holes, and as the side
a' is moved to and fro, the wires enter and leave
the holes, and so keep the holes free. Proper ap-
paratus for forming the furrows may be attached
to the front of the machine.

against the projecting pieces d fixed to the moveable side a' of the hopper, and so give to it a vibratory motion. The moving the side a' towards and away from the side a2 allows the seeds or manure to fall on to the blades e on the axis f, and as the axis rotates, the seeds or manure fall on to the board l, and the vibratory motion of the side a' also keeps the manure in the hopper agitated. The board / at one edge turns on the hinge m, and a vibratory motion is communicated to this board by its being connected by the chains n to the vibrating side a' of the hopper, and the seed or manure will thus be shaken off this board on to the land. The hinge c, upon which the moveable side a' turns, can be raised or lowered by screwing or unscrewing the nut c', and the distance between the end of the side a' and the lower part of the side a' can thus be varied, and by this means the amount of seed or manure distributed on to the land can be varied. When it is desired to stop the seed or manure from descending from the hopper, the end of the side a' can be drawn against the side a by depressing the long arm of the lever o. A greater quantity of seed or manure may be allowed to fall from the hopper by turning the pieces d d, so that they are not acted on by the teeth e on the axis f; the teeth e will then strike against the end of the moveable side a' of the hopper. A still greater amount of seed or manure may be allowed to fall from the hopper by raising the side a of the hopper away from the blades on the axis f; for this purpose the side a2 is carried by hinges which can be raised or lowered in a similar manner to the side a'.

In arranging the apparatus for distributing seeds or manure in furrows, a box containing the

AND STOPPING RAILWAY TRAINS.

By ALEXANDER ALLAN, Engineer, Perth.
IN the prevention of collisions, and their conse.
quently serious results, a few seconds are most
valuable: the danger also is, in most cases, first
seen by the man in charge of the engine. The
object of these improvements is, therefore, to give
the driver increased power of controlling the speed
of, and in stopping the trains; and for this pur-
pose, and in order that the whole break power of
any train may be brought into requisition in the
shortest possible time, it is recommended that, in
addition to the apparatus to be hereinafter de-
scribed, a cord shall be placed within convenient
reach of the men on the engine, communicating
with a bell fitted up in the first break-van, by
which means the guard may be apprised of his
assistance being required at the van-breaks.

The improvements consist of two distinct parts.
1st. By inserting a throttle or other valve in the
exhaust-pipe of the engine at 4, so that by means
of a connection B the driver can fully or partially
close the valve A. By the table of experiments
appended, it will be seen, that by the closing of
this valve (the regulator being at the same time
open), a retarding force is opposed to the engine
of equal power with the tender breaks, and for all
ordinary stoppages this can be used to bring the
train almost to a dead stand-the tender break
being applied only for say the last dozen yards,
thus effecting a great saving in the permanent
way, tender-tyres, and break-blocks.

The second part of the improvements consists of a steam break to work in connection with the above valve in cases of great danger. The steam is taken from the exhaust-pipe by means of the pipe C which is supplied by a stop-cock or valve

By partly closing (more or less) the throttlevalve, trains may be controlled when passing down steep inclines to any desired speed, leaving in reserve (in the case of heavy goods trains especially) a great surplus of break-power to bring the train to a stand quickly on any inclinenamely, that of the steam-break herein described, and also that of the tender and van-breaks. In illustration of this, an experiment, not included

of five miles, the gradients averaging 1 in 80 (de scending), and with a gross load, estimated at 200 to 210 tons, the throttle valve alone controlled the train from a starting speed of thirty miles per hour to fifteen miles per hour over the whole distance.

The partial closing of the valve may also be made to prevent violent slipping, as the wheels will only revolve in proportion (i.e., the traction will only be equivalent) to the quantity of steam allowed to escape from the exhaust-pipe, and this may be regulated to any extent by the valve, which can be worked with greater ease and nicety than the regulator.

With regard to reversal, it is known to be extremely difficult, if not impossible, to reverse an engine at speed, but it will be seen that, with full steam on the pistons, the closing of the throttlevalve, which is not effected by speed, produces a result quite equal to that of reversal, whilst reversal itself is facilitated by a greater equalisation of the pressure on both sides of the valves, and an increased break-power is obtained (see Table) without the usual objectionable results of reversing the engine whilst in motion.

The combined effect of these appliances may further be shortly stated to be,

1st. By the throttle-valve alone a power is exerted equal to that of the tender breaks.

2nd. By use of the tender-breaks in combination with the above, a doubling of this power is obtained

3rd. By using the engines' steam break-blocks, the throttle valve, and the tender breaks together, a retarding power equal to triple that of the tender breaks alone is brought out.

4th. In addition to the above, by reversing,

which when transversely twisted, thus,

ship counter," as Sir Howard very justly remarks, | flue of the heather, made out in the rough the
"the water which is divided by the body of the following models:-

ship subsequently flows obliquely towards the
screw; and again, the water, after being pressed
by the screw, is broken by the stern-post and
rudder, where being arrested, part of it is forced

and fixed on its axle, gave this next transfigura- forward in the direction of the ship's motion."

tion of its economy:

This prodigious effort of poor George's, though considered the best serew of the day, succeeded by Ericcson's which much resembled it, and the Smith's, Brown's, Jones', and Robinson's imitations of them being somewhat overlaid with science, inasmuch that it was not calculated to give motion until the completion of its first revolution, as well as to sustain the pressure of the ship's way at fifteen knots an hour, (which is calculated to be six tons on the point opposed to its resistance supposing its diameter twelve feet,) was soon set aside, as all screws ultimately will be, for the propeller, which George at first, as has been shown, started with. So without much ado, the old idea of the mop-stick came into vogue again, and forthwith grew out of it the following invention, the mutton bone, in a very great degree, serving as the pattern in the shape of a fan at an angle at 45° of its axial motion :

sole inventor.

A the back of an
oar blade;

:

Doubtless, this is a serious objection to the fair-
play of the screw's action; and if the pressure of
motion is as the cube of the screw's diameter, as
much power of propulsion is lost as that back
pressure retards it, particularly as the gyrations
of an eddying volume of water act impulsively
upon its revolutions. "Another objection to the
screw in its present position of the vessel," con-
tinues Sir Howard, "is, that the shake of the screw,
and the consequent injury to the stern of the
ship, are caused by the sudden and violent reactions
of the disturbed water in that place against the
blades of the screw as they enter and emerge from
thence." But the remedy proposed in rounding
the fans of the screw, or whether they be angular
or semicircular, does not appear fairly to meet the
objection, since the stroke of its diameter must
determine its force. To give this ingenious inven-
tion fairplay surely it is necessary to disentangle
it of all such impediments (as described by Sir
Howard). If at the stern of a vessel the plung-
ing against the screw of the eddy and the dis- Now you see, Sir," continued the animated old
turbed current of the ship's way distracts its gentleman, "by reducing the fans to a pair,
motion, surely there is a remedy at hand in fit-twisting them inversely at an angle of 45° of each
ting it to the bows of a ship before or after its other, and inserting them at the end of a split
cut-water, where the undisturbed action of the
stick, thus,
fluid's equal pressure would give a steadiness of
motion irrespective of such fatal objections.

B the front ditto;
Ca fairy wheel.

Whilst passing in review the subject of the screw, or more properly propeller (since it has no property in common with the former in the water than a figure of 8 has above it when cut out by a skater), a further and equally interesting anecdote of its invention, more recently than that just described, may not prove uninteresting to those who lean rather to sympathy with original genius and then through a tube to my clockwork in than to a worship of the wealth accumulated by the boat, my screw its practical application. To Mr. Farquhar, of Tower Hill, the eminent chronometer maker, be then the honour due in his own words, of the re

After a world of hard labour, as he termed it,vival of its discovery. "Sir," said the old genGeorge, after boxing the compass of all the angles tleman, after hearing the errand, and measuring under the sun, and making the machine describe his inquirer's mental stature under the deep and as many circles in an hour as gyrations are per- thoughtful brows of a northern head that had formed on a windy day, as the gardener said, by a won its mechanical immortality-"Sir," continued cherry clapper, finding the principle of its action he, "your introduction by my friend is your welthe correct one, at once sought out for the means come. Sit down, Sir. Well, now you must know, to protect it in a patent, then requiring some Sir, taking the morning air as I usually did thirty hundreds of pounds to complete it. Of course, years since over the drawbridge of the London like many as good or better men before him under Docks, my attention was arrested by a youth about like circumstances, George's little castles in the air twelve years of age propelling, or sculling, as it is came to the ground for his want of capital, crush- called, a boat by its stern in a manner so unusual ing his hopes in their fall as he saw rise from as to excite my unbounded curiosity, and to their ashes a hundred of his wealthy imitators, venture in me a thought of its transference to now many of them enjoying the proceeds and circular motion. Ever delighted at improvement premiums of the wreck of the genius of the screw's for our countrymen never throw a chance of advantage away, as you southerns good-humouredly say, honestly acquired-I was at once delighted and instructed, and the lad and I were the best friends in the world long after; he for the value to me of his skiff, and I to him of the means of earning myself, of six feet stature, unable to swim, and an honest penny. It was no little trial, to one like burly withal, as you may suppose, Sir, when the tide at times ran wildly, to adjourn with him to the deep-water of the Lea, there to abide the rocking to and fro of his little cockle-shell, not more than double my length, and of such slender proportions as to require my holding on its gunwales with a tenacity and grip with which you know, Sir, my countrymen, in common with all, ever hold their own with. However, giving the lad a fair price for his lesson, my best wits, after putting together and pulling to pieces as many bits of tin, models of little ships, some with holes at their sterns, and others with wells in their middles, as would fill garret, and coupling what I had learnt of the children we all have delighted in during windy skiff's motion with that of a fairy wheel, which as weather, as it skims along the ground like the

It is rather a remarkable feature in the imitations of the screws of George Blencowe, from the first which he had permission to try on the lake of Captain Trotter's park at Totteridge, in Hertfordshire, to that which he had perfected in 1832, now used with a trifling deviationfrom its original by the Great Eastern, none seem to have got the correct angle of 45° of their axial motion. And though science is indebted to Sir Howard Douglas for his animadversions on many similar faulty inventions, yet is but little additional knowledge to be gleaned about the screw in his little work on Naval Warfare, replete as it is with great modesty and ability. There is one remark, however, about the disadvantageous position of the screw under the ship's counter deserving the greatest attention, not the less for its ever having been a point in debate amongst scientific men from its first invention, than for the stubborn perseverance in the present practice of its faulty situation. "From the position of the screw in an aperture close under the "On Naval Warfare," p. 37. Murray, London, 1858.

a

as my heart seemed to respond to its motion spun away my model after the following fashion, from one side to the other of the creek, as true as a water-rat":

"Statement of William Farquhar, the real Inrcot
of the Universal Under-water Propeller, claim
and patented by Lieutenant Carpenter.
"If the government of this country, of whatever
justice to individuals, however obscure, who had a clear
party, had not shown invariable disposition to do
and dispassionate case to present, the undersigned
would hesitate to solicit attention to this statement.
If a right could cease to be a right, because he wo
had it lacked means to bring it under the notice of
those influential to recognise it, the writer of this
statement would despair of the justice he now seeks.

"In 1828 (so far back as this date) I, the under signed, William Farquhar, was in the employ of Mr. Grant Preston, a relative, a well-known inventor, to whom the navy owes the Ship Deck Lights still in use. The constant talk of naval improvements going on in that society first turned my mind to inventions, of which in my time I have perfected several. Standing one day in the London Docks on one of the swingbridges, I noticed under me a man scadding a boat, when it instantly occurred to me that the oblique I went home, and found three persons (two of whom action of the oar could be produced by wheel-work. are now living) and proposed the thing to them.